This information is for people who have eczema. It tells you about watching what you eat when breastfeeding, a treatment used for preventing eczema. It is based on the best and most up-to-date research.
Does it work?
We don't know for certain. If eczema runs in your family, watching what you eat when you're breastfeeding could prevent your child getting eczema. But we need more research before we can be sure.
What is it?
Many people are allergic to some foods. And many people think that there could be a link between food allergies and eczema flare-ups in some people. Milk, eggs, citrus fruits (including juice), chocolate, colourings, and peanuts cause the most allergic reactions in young children.   Things (including foods) that cause allergies are called allergens.
In some people who have eczema, food allergens seem to trigger symptoms. Some doctors believe that if you think your child is allergic to a food, then taking that food out of the child's diet may help relieve eczema symptoms.  This is called 'dietary manipulation'. (See Changing what you or your child eats for more information.)
Some specialists also think that very young babies should avoid these allergens. This means that the mother avoids suspected allergens in her diet while she's breastfeeding the baby. 
In one of the studies that we found, pregnant women and breastfeeding mothers were advised to avoid all milk. In another study, they were advised not to eat any dairy products, milk, eggs, fish, beef, or peanuts. 
How can it help?
If people in your family have eczema (or if they have asthma or hay fever), your child is at risk of getting eczema, too.
One study found that if you avoid milk when you're pregnant and breastfeeding then your baby is less likely to get eczema in the first 12 to 18 months of his or her life.  But many other studies found that avoiding certain foods makes no difference to whether a child gets eczema. 
How does it work?
Some doctors believe that because some children are allergic to certain foods, those foods can cause eczema.  
The thinking is that when babies are very young, they can become oversensitive to some foods. 
If that's true, a mother who doesn't eat these foods while she's breastfeeding may be able to prevent her child from becoming allergic to them. 
Can it be harmful?
We found no evidence of any harms from women avoiding certain foods while they're breastfeeding.
How good is the research on watching what you eat while you're breastfeeding?
There isn't good evidence that avoiding certain foods during pregnancy helps protect children from eczema. We found one big summary of the research (called a systematic review) that looked at the results from three studies. One of these studies found:  
Only 2 in 10 of the children born to mothers who avoided milk while pregnant and breastfeeding went on to get eczema
4 in 10 of the children born to mothers who ate an unrestricted diet went on to get eczema.
The other studies in this summary weren't well designed so their results are not reliable. We need more research before we can know for certain if you can prevent eczema in this way.